Fuel accumulator lines are used in the range of automotive engineering to set up a common rail injection system. The fuel accumulator line is then used as a storage volume in which a fuel at a relatively high pressure can be kept ready. The fuel is released into the combustion chamber of the internal-combustion engine via injection valves allocated to the fuel accumulator line. The fuel accumulator line is used for direct fuel injection in both petrol and diesel internal-combustion engines.
For a precise and efficient injection, a very high pressure in the fuel accumulator line is desirable, particularly in the case of diesel fuel injection. In the meantime, pressures of 1500 to 2000 bar are reached. This pressure range in particular makes very high quality demands on the fuel accumulator line. Particularly, the connection of a line to the fuel accumulator line is a critical function that has a great influence on the quality of the fuel accumulator line. In order to connect a line, a hole in the wall of the fuel accumulator line is required. A wall with a hole has the disadvantage that cracks form in the area of the hole which subsequently ruptures under high pressures. In addition, it is necessary to press the line under high pressure against the fuel accumulator line to form a seal against the high pressures.
In order to connect a line to the fuel accumulator line it is well-known from DE 3 817 413 Al to arrange, for example, a circular connecting piece in the area of a connection bore of the fuel accumulating line. The connecting piece includes the fuel accumulator line in the area of the connection bore and has a thread. The thread is used for screwing in a retaining nut by means of which a line to be connected to the fuel accumulator line is prestressed in the direction of the fuel accumulator line. Because the connecting piece includes the fuel accumulator line, the line can be prestressed against the fuel accumulator line with a relatively high force. For purposes of better fastening, the connecting piece must be connected to the fuel accumulator line via a welding seam.